$100 discount if you can say that Panasonic lens name fast, 10 times. OK, kidding.
There is one and only one lens that never fails to reward me on Micro Four Thirds: the Panasonic Leica 25mm f/1.4 DG Summilux. It is by far my lens of choice on the Olympus E-M1 (or the E-M5 before that). It has that Leica look, as I think my coverage demonstrates, such as the Lundy Canyon Morning examples. And it nailed focus in virtually every situation with the E-M1.
Now along comes a hefty telephoto sibling, the Panasonic Leica DG Nocticron 42.5mm f/1.2 ASPH which promises equally gorgeous and perhaps even more appealing image quality. For one thing, the lens diaphragm (just examined in my review sample) is about as circular as I’ve seen in any lens (to the extent of making it difficult to count the 9 rounded aperture blades!), suggesting that lens bokeh might have that extra edge.
As a huge plus, B&H is also loaning me the Voigtlander 42.5mm f/0.95 Nokton, which is a stop faster, heavier (metal build) and built like a Zeiss ZF.2 lens. Built-to-last feel, superb (!) aperture and focus rings (manual focus), and while the 10-bladed aperture is not as rounded as the Panasonic 50/1.2, it is perfectly symmetric with stopping down.
I’ll be working with these two lenses over the next few weeks on the Olympus E-M1, results to be posted in Guide to Mirrorless. My hunch is that the manual-focus Voigtlander might be preferred by video shooters (for its manual control), and the Panasonic by others, but that remains to be seen.